grafana: drop alerting Service and POD_IP env owned by grafana-operator (#510)

grafana-operator already creates the headless `grafana-alerting` Service (port 9094) and injects `POD_IP` into the grafana container, so the copies added in #509 make Argo CD and the operator fight over the same objects.

- remove `service-alerting.yaml` from the grafana base
- remove the `POD_IP` env entry from the Grafana CR
- keep the `unified_alerting` `ha_*` config, which targets the operator's Service

Reviewed-on: #510
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/base/grafana/grafana.yaml

@@ -22,10 +22,6 @@ spec:
           containers:
             - name: grafana
               env:
-                - name: POD_IP
-                  valueFrom:
-                    fieldRef:
-                      fieldPath: status.podIP
                 # DB password + OAuth client secret injected from the
                 # Vault-synced secrets (GF_ env overrides grafana.ini).
                 - name: GF_DATABASE_PASSWORD

apps/base/grafana/kustomization.yaml

@@ -10,7 +10,6 @@ resources:
   - vaultauth.yaml
   - vaultstaticsecret.yaml
   - grafana.yaml
-  - service-alerting.yaml
   - grafanadatasource.yaml
   - gateway.yaml
   - httproute.yaml

apps/base/grafana/service-alerting.yaml

@@ -1,20 +0,0 @@
----
-apiVersion: v1
-kind: Service
-metadata:
-  name: grafana-alerting
-  namespace: grafana
-spec:
-  clusterIP: None
-  publishNotReadyAddresses: true
-  selector:
-    app: grafana
-  ports:
-    - name: gossip-tcp
-      port: 9094
-      targetPort: 9094
-      protocol: TCP
-    - name: gossip-udp
-      port: 9094
-      targetPort: 9094
-      protocol: UDP